Brandy is really good about coming when called- most of the time. The problem I am having is that every once in a while she will stop and look when I call, but then either go on about what she is doing, or even run farther off. This doesn't happen on a regular basis, maybe less than once a week, but I don't want it to happen at all. I use treats and praise to reward her for coming, and she is also trained to come to a shaker can. Neither the come command nor the shaker can work when she decides to disobey. What should I do?

Either make yourself more enticing when this happens (run backwards, use playful body language, drop down to the ground, etc.) or have her wear a long line for a few weeks so that if she ignores a come command you can reel her in. The main goal in either case is to not let ignoring work. I would also suggest using higher quality treats reserved for come commands only. And just in case you aren't already doing this, you want to release her back to what she was doing the majority or the time you call her so that following the command rarely has bad results like having to leave the park or go inside.

Either make yourself more enticing when this happens (run backwards, use playful body language, drop down to the ground, etc.) or have her wear a long line for a few weeks so that if she ignores a come command you can reel her in. The main goal in either case is to not let ignoring work. I would also suggest using higher quality treats reserved for come commands only. And just in case you aren't already doing this, you want to release her back to what she was doing the majority or the time you call her so that following the command rarely has bad results like having to leave the park or go inside.

^ This.

I will also say (and hope to not be flamed for it), that with Cynder and Cooper we (or should I say Mike, because I wasn't comfortable with it) used an e-collar to proof their recalls. For Cynder it was just a reminder as she was taught all of her off-leash manners via an e-collar when Mike first adopted her, but it was Cooper's first experience with an e-collar. It took about two weeks of Mike working with him, but by golly if his recall isn't great now. You just say his name and as long as he's not on the hunt to do his business he'll book it back to you full speed, as excited as can be.

Although I do plan to do the baseline off leash training with Future Puppy in a purely positive sense (special recall word, high value rewards, long line work, etc.), I won't be opposed to proofing with an e-collar should the need arise after I've seen how well Cynder and Cooper responded to it.

Thanks, everyone. I have a tritronics collar that I got for Rita because she was endangering herself, (we live with cougars). But I'm not going to use it if I don't have to. I'll make her some liver treats, and if that's not foolproof, try the long line. We are working her on tracking, but mostly using hot dogs, so hopefully the liver will work.

I always taught come using high value treats and jackpot rewards, and pretty much the technique Maxy posted. It's always worked pretty well

But with Bailey, I did the Whiplash Recall training I read about in the Control Unleashed book.
To most (non-dog) people, it probably looks about the same, but for me - it is sooo much faster... instant, reliable. There's no hesitation - as soon as I say her name her face whips around, and then the rest of her body follows with a come. When I ask for a come, I actually expect a "come front" (like for RallyO). I want them to come and sit in front of me within arms reach until released. Which is always good if I need to leash-up, or keep them close just in case of any kind of situation. I preferred it so much, that I started over and taught Maddie using the same method

I highly recommend the book, but there are also a lot of videos and such on youtube if you do a search. I did a quick one for you because I wanted to c&p a link for you http://www.youtube.com/watch?v=Fl2bJ2kJdfM

Another thing I wanted to add, is when your practicing recalls is to make sure your ending on a good note. If coming when called = leash up and leave the fun at the end of the day, try to avoid that!